VirtualBox USB Error Under Ubuntu Linux

I've installed VirtualBox on several Ubuntu Linux machines and I usually get this error when I launch VirtualBox or navigate to the settings for a virtual machine.

Could not load the Host USB Proxy Service (VERR_FILE_NOT_FOUND). The service might be not installed on the host computer.

I found the solution below at https://bugs.launchpad.net/ubuntu/+source/virtualbox/+bug/151585.

Open the /etc/init.d/mountdevsubfs.sh file.

Find the following lines:

#mkdir -p /dev/bus/usb/.usbfs
#domount usbfs "" /dev/bus/usb/.usbfs -obusmode=0700,devmode=0600,listmode=0644
#ln -s .usbfs/devices /dev/bus/usb/devices
#mount --rbind /dev/bus/usb /proc/bus/usb

Remove the comments (#) so that the lines look like this:

mkdir -p /dev/bus/usb/.usbfs
domount usbfs "" /dev/bus/usb/.usbfs -obusmode=0700,devmode=0600,listmode=0644
ln -s .usbfs/devices /dev/bus/usb/devices
mount --rbind /dev/bus/usb /proc/bus/usb

Restart using the following commands and then close and re-open VirtualBox. Your USB devices should be recognized.

/etc/init.d/mountdevsubfs.sh stop
/etc/init.d/mountdevsubfs.sh start